Set each option’s type, direction, strike, premium per share, contracts and explicit multiplier. The default multiplier is 100; verify the actual contract. Stock legs use shares and cost basis. All option legs use one common expiry. Read whole-position scenario P/L, exact expiry break-even points or zero intervals, and global maximum gain and loss. The scenario grid uses the same modeled maximum-loss return basis as the summary.

Expiry payoff and return basis

Sum each signed intrinsic value less signed entry premium, scaled by contracts and the selected multiplier, then subtract both explicit fees. Stock P/L is signed shares times terminal price less cost basis.

Solve each straight payoff segment between zero and the strikes, including the final unlimited-price segment. A touching root and an interval of zero P/L are distinct; chart zoom does not set the root domain.

Return divides scenario P/L by a positive finite modeled maximum loss. It is unavailable for zero or unbounded loss. This denominator is not a broker margin requirement or a return on buying power.

Expiry uses intrinsic value. Today and halfway curves and Greeks use Black-Scholes-Merton assumptions. The displayed profit probability uses the model’s risk-neutral distribution, not a forecast of actual trading success. Early exercise, assignment, mixed expiries and changing volatility are not modeled.

Opening commission and the chosen terminal fee are charged to every option contract in every scenario, including out-of-the-money contracts. Stock fees, bid-ask spreads, taxes and assignment costs are excluded. This calculator does not estimate tax treatment.

Inputs, scale and scenario comparison

Set each option’s type, direction, strike, premium per share, contracts and explicit multiplier. The default multiplier is 100; verify the actual contract. Stock legs use shares and cost basis. All option legs use one common expiry. Read whole-position scenario P/L, exact expiry break-even points or zero intervals, and global maximum gain and loss. The scenario grid uses the same modeled maximum-loss return basis as the summary. Enter spot, volatility, days to expiry, interest and dividend rates. Set opening commission and a separate terminal fee per option contract; enter zero for any fee you are not modeling. The default multiplier is 100, but the selected multiplier is explicit and must match the contract. A different number changes payoff scale; it does not add support for other settlement rules. Maximum gain and loss include the selected fees and the zero-price boundary. A positive or negative right-tail slope identifies unlimited gain or loss. Maximum gain is zero when no positive payoff is possible.

Independent arithmetic checks

Set both fees to zero for these arithmetic examples and use a multiplier of 100. A long put with strike 100, premium 5 and one contract returns 9,500 when the underlying finishes at zero: intrinsic value is 10,000 and the entry premium is 500. For two long calls with the same strike and premium, a final price of 120 gives intrinsic value 4,000 minus premium 1,000, producing 3,000 profit and 300% return on modeled maximum loss. A bullish call spread buying strike 100 for 4.50 and selling strike 110 for 1.50, one contract each, has debit 300, maximum loss 300, maximum gain 700 and break-even 103. A credit put spread selling strike 100 for 5 and buying strike 90 for 2 instead has credit 300 and maximum loss 700; profit 300 therefore gives 42.9% on this risk basis. Scaling every contract quantity scales both profit and loss, preserving that return percentage. Adding fees reduces payoff and can move the roots. Zero contracts represent zero exposure; an empty position has no positive maximum-loss denominator, so a return percentage is unavailable. Invalid or fractional contract quantities remain uncomputed.

Interim views and reviewed comparisons

Select whole days from today to the common expiry to inspect an interim scenario. The expiry hero and global maximum loss still refer to intrinsic payoff at expiry. Interim curves use European Black-Scholes with constant IV, rates and dividend yield; both selected contract fees are deducted without discounting. Zero IV leaves interim option valuation unavailable. Individual leg lines sum to the selected total. Delta, gamma, theta, vega and rho describe local model sensitivities, not promised outcomes. Theta holds other inputs fixed; its sign depends on moneyness, rates, dividends and remaining time. A deep-in-the-money long European put can have positive theta at positive rates; the matching short position reverses it. Capture reviewed legs as B, then edit A. Both comparisons use the current market, expiry scenario and fees, while preserving original cash and maximum-loss amounts. Normalization uses an equal positive finite modeled loss budget; it does not create tradable fractional contracts. Remember is optional. Sharing starts with a blank preview; including inputs discloses both reviewed positions and their assumptions.